Self-monitoring controller for quartz crystal Microbalance sensors

ABSTRACT

A controller for a quartz crystal microbalance (QCM) sensor system and method for detecting mass deposition on a QCM sensor. The controller controls a QCM using temperature-, voltage- and current-regulating circuits, a microcontroller, an oscillator, heating and cooling devices and circuits, high voltage grids, digital-to-analog and analog-to-digital converters, data telemetry and uplink circuits, and a remote user. The remote user may be a person, computer, network or data logger. The remote user allows the controller to be reconfigurable during operation. The controller samples and reports data faster and is more reliable over extended periods of operation. Further, the controller is assembled using innovative techniques making it smaller and thus more transportable, easier to incorporate into existing facilities and less expensive to construct and operate. The apparatus may also be assembled in a modular fashion that allows for customization.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Application No.60/162,792, filed Nov. 1, 1999, which is incorporated by reference inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of electronic controlcircuits for microelectronic measuring devices. Specifically, theinvention relates to software-driven microcontroller and electroniccircuits for monitoring and controlling quartz crystal microbalance(QCM) sensors, which are highly accurate devices for detecting minutequantities of mass deposited on the face of a crystal.

2. Description of the Related Art

QCM systems have been used for over two decades to measure minutequantities of mass. The principal components of a QCM system include aQCM sensor, an oscillator and control circuitry. In a QCM sensor thereare typically two carefully matched quartz crystals as aligned parallelto each other and separated by a small gap. Only one of the crystals,however, is exposed to the outside environment. The difference infrequency between the two crystals is the beat frequency, which is avery sensitive indication of the mass being deposited on the exposedcrystal surface. The beat frequency is proportional to the mass ofcontamination that has accumulated on the sensing area and iselectronically recorded in a digital electronic counter. Because QCMsystems can measure very small amounts of mass deposited, they are oftenused when precise control over a system or process is desired or tomonitor an environment.

QCM sensors have been used in spacecraft, for example, to measure filmdeposition on sensitive surfaces such as optical mirrors, thermalradiators and solar arrays. They have also been used in gas detectionsystems to measure contaminant concentrations in an ambient or closedenvironment. Still other QCM sensors have been used in semiconductorprocessing to precisely control chemical deposition in vacuum chambersand to monitor clean room contamination.

Control circuits associated with QCM sensors have been used almost aslong as QCMs have existed. Conventional controls include an assembly ofcircuitry and sensors which may or may not consist of a QCM sensorsignal conditioner, a QCM sensor temperature monitor, a thermal-electricheat pump controller and a microcontroller for data acquisition and dataformatting. These elements have been collectively referred to as QCMcontrollers, controllers, or control circuits.

Requirements for control circuits are as varied as the applications forthe QCM sensor. For example, QCM sensors that are moved in and out of aliquid environment have been fitted with controllers adapted to measurethe sensor's resonant frequency over a wide range of impedance. OtherQCM sensors that are used to measure the mass of a substantial drop ofliquid or particulate matter have been designed to correct forsignificant viscous damping losses. Still other QCM sensors that areused to monitor chemical environments have been constructed with controlcircuits that trigger an alarm and warning system. These controllers aretypically to constructed in large housing units with control panels andreadout devices that impose significant weight and power resourcerequirements. As in most applications, the QCM sensor and controller areaccessible; therefore, self-monitoring and wireless telemetry are notneeded. Further, present controllers merely control the QCM sensortemperature. Additionally, conventional systems generally require a userto upload commands off-line or directly into the controller from akey-pad on the face of the controller box or from a key-board connectedto a computer that is connected to the controller.

As QCM systems have found their way into spacecraft, missiles, andchemical applications, the need for small, lightweight, reliable,cost-effective, remotely-accessible systems capable of operation inextreme low temperatures has been observed. Further, in addition todetermining mass, it is highly desirable to determine the electroniccharge of particles and the molecular species of the material depositedon the QCM sensor's quartz crystal. Current QCM systems do not includethese desirable features.

SUMMARY OF THE INVENTION

It is an object of the invention to provide for the monitoring andcontrol of a microelectronic sensor system.

It is a further object of the invention to provide an apparatus thatself-monitors the health of one or more QCM sensors using amicrocontroller with computer program instructions capable ofcontrolling the QCM sensor temperature and monitoring the QCMtemperature, beat frequency and controller operations, among otherthings.

It is another object of the invention to provide for a communicationssystem using data telemetry and uplink circuits that allow a remote userto retrieve processed data and to send commands as needed to ensureproper operation of the QCM sensor system or allow the software-drivenmicrocontroller to make adjustments.

It is still another object of the invention to provide for extendedoperations without taxing finite weight, energy and cost limits such asthose imposed in space flight operations.

It is still another object of the invention to operate at extreme coldtemperatures, such as those experienced in outer space.

It is still another object of the invention to capture electronicsignals including, but not limited to QCM beat frequency, duty cycle,and amplitude and QCM sensor and controller temperature current, convertthe signals to data records and then report the data quickly to a remoteuser to enhance the system's capability and reliability overconventional systems.

It is still another object of the invention to provide a controllerusing innovative nano-connectors and miniature wiring to achieve a100-fold reduction in size compared to conventional controllers therebymaking the present invention portable and easy to incorporate intoexisting facilities that have limited space. This also provides forreduced construction and operating costs.

It is still another object of the invention to be assembled in modularunits thereby being highly flexible.

It is a further object of the present invention to provide a controllerthat is modifiable by a user so that it can be reconfigurable duringoperation.

These and other objects of the invention are described in thedescription, claims and accompanying drawings and are accomplished by acontroller, for controlling an apparatus including a microelectronicsensor and for conditioning electronic signals having associatedtherewith electronic circuits and self-monitoring software. Thecontroller includes a controller thermal monitor for detecting atemperature of the apparatus and outputting a controller temperaturesignal, a first temperature measuring circuit for detecting thecontroller temperature signal from the controller thermal monitor, asecond temperature measuring circuit for detecting a temperature signalfrom the microelectronic sensor and outputting a current signal, asignal conditioning circuit for receiving and conditioning a beatfrequency signal from the microelectronic circuit, a microcontroller,connected to the controller thermal monitor, the first and secondtemperature measuring circuits, and the signal conditioning circuit, forconverting the controller temperature signal, the microelectronic sensortemperature signal, the current signal, an amplitude of the beatfrequency signal, a voltage from the microelectronic sensor, and thebeat frequency signal into data records and for manipulating the datarecords for transmission. The controller can also include athermal-electric heat pump circuit, connected to the microelectronicsensor and the second temperature sensing circuit, for detecting thetemperature signal from the second temperature sensing circuit andoutputting an electric current and for heating and cooling themicroelectronic sensor by switching the direction of the electriccurrent, and a power switch for energizing the microelectronic sensor.

The present invention also includes an apparatus for controlling amicroelectronic sensor and conditioning electronic signals havingassociated therewith electronic circuits and self-monitoring software,including a sensor circuit, for precisely detecting temperature andminute changes in mass deposition and outputting a temperature signalassociated with a temperature and outputting a beat frequency signalproportional to said mass deposition and a controller circuit formonitoring the health of the sensor means and conditioning the beatfrequency signal. The controller circuit can include a controllerthermal monitor for detecting a temperature of the controller circuitand outputting a controller temperature signal, a first temperaturemeasuring circuit for measuring the controller temperature signal fromthe controller thermal monitor, a second temperature measuring circuitfor detecting the temperature signal from the sensor circuit, athermal-electric heat pump circuit for receiving an electric current andfor raising or lowering the temperature of the sensor circuit byswitching direction of the electric current to the thermal-electric heatpump and for turning off the heat pump, a signal conditioning circuitfor receiving and conditioning the beat frequency signal from the sensorcircuit and a microcontroller, connected to the controller thermalmonitor, the first and second temperature measuring circuits, thethermal-electric heat pump circuit, and the signal conditioning circuit,for converting the controller temperature signal, the sensor circuittemperature signal, the second temperature measuring circuit current,beat frequency and amplitude, microelectronic sensor voltage, and thebeat frequency signal into data records and for manipulating said datarecords for transmission.

The sensor circuit can be any QCM.

The controller circuit can further include a remote user for providingcommands remotely, a power switch for energizing power to the sensorcircuit, an uplink circuit for receiving commands from the remote userand a telemetry circuit for capturing data records and transmitting datarecords to the remote user.

The thermal monitor can be a platinum resistive temperature device, athermocouple, or other thermal monitor device.

The sensor circuit can further include a high voltage grid forattracting specific charged particles for mass measurement by switchinga polarity of the high voltage grid to either positive or negative withreference to ground and an insulator for insulating the sensor circuitfrom the electric current from the high voltage grid and the sensorcircuit.

The apparatus may be part of a system that is used in a chemicaldeposition process, space flight operations, to monitor for chemicalcontamination in an enclosed or ambient air environment, and/or forbiological detection.

The apparatus may include a computerized method for controlling a QCMsensor, the method includes the steps of initializing system variablesand establishing default and set-point values; energizing a potentialacross QCM sensor system terminals, thereby energizing QCM sensor quartzcrystals, a thermal-electric heat pump, and a high voltage gridcontained within the QCM sensor; detecting the voltage signal amplitudeand voltage signal frequency of the QCM sensor system quartz crystals,the voltage amplitude of the QCM sensor system thermal monitor, and thecurrent of the controller thermal monitor and QCM sensor power supply,and producing individual signals representative thereof; amplifying thequartz crystal voltage amplitude signal and calculating the duty cycleand waveform thereof; supplying the previous signals and the calculatedduty cycle and waveform calculated above to a microcontroller forconversion into data records; comparing the data records to the defaultor set-point values; adding synchronization codes to the data records;transmitting the data records through a wired or wireless communicationssystem to a remote computer or computer network; receiving incomingcommands from the remote computer or computer network; and adjusting thevoltage supply to the thermal-electric heat pump as a result of theincoming commands of the deviation from the default or set-point values.Moreover, the method may also include the steps of slowly heating theQCM sensor quartz crystals and detecting the voltage signal amplitudeand voltage signal frequency of vibration of the QCM sensor systemquartz crystals over time; calculating a sublimation and evaporationtemperature corresponding to the material deposited on the QCM quartzcrystal; and supplying the voltage signal amplitude and voltage signalfrequency associated with the QCM sensor system quartz crystals and thesublimation and evaporation temperature corresponding to the materialdeposited to the microcontroller for conversion into data records.

These objects, together with other objects and advantages which will besubsequently apparent, reside in the details of construction andoperation as more fully described and claimed hereinafter, referencebeing had to the accompanying drawings forming a part hereof, whereinlike reference numerals refer to like parts throughout.

DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of an example of a QCM sensor system accordingto the present invention;

FIG. 2 is a block diagram of an example of a QCM controller apparatusthat is part of the QCM sensor system according to the presentinvention;

FIG. 3A is a three-dimensional diagram of the physical apparatus of theQCM sensor system according to the present invention;

FIG. 3B is a detailed diagram of the various circuits in FIG. 3A;

FIG. 4 is a three-dimensional diagram of the QCM controller apparatusaccording to the present invention;

FIG. 5 is a diagram of the QCM sensor system high voltage grid accordingto the present invention; and

FIG. 6 is a flow chart explaining how the controller controls dataacquisition and processing associated with the QCM sensor.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram of a QCM sensor system 20 according to thepresent invention, which comprises a bus 50, a controller 100, whichincludes a microcontroller 105, one or more QCM sensors 300, and aremote user 500. In this example, the controller 100 and QCM sensors 300may be connected by nano-connectors or miniature wiring 340 (FIG. 5) toreduce the size and weight of the QCM sensor system 20.

The QCM sensor system 20 can provide both analog and digital telemetrystreams of monitored and processed date. Miniaturized connections 340(FIG. 5) used between system components are, for example, produced byNanonics Corp.; however, any equivalent connectors can be used.

Data are transferred through the bus 50 at preferably an eight- orsixteen-bit transfer rate and at a frequency consistent with the datasampling and telemetry rate of the system.

The controller 100 can support multiple QCM sensors 300. In manyinstances, two QCM sensors 300 are practical, and in this example, twosensors 300 are controlled.

Each sensor 300 may include first and second quartz crystals 305 and 315(QC,a and QC,b), respectively, a thermal (temperature) monitor 310 (TM),a thermal-electric heat pump 320 (HP) for adjusting sensor temperature,a frequency mixing circuit 325 (FM), which receives signal from thequartz crystals 305 and 315 and outputs a beat frequency signal, a highvoltage grid 325 and an insulator 330. According to the presentinvention, two quartz crystals are used. The invention, however, can bemodified to include a single crystal deposition monitor where there isonly one quartz crystal and a thermal electric heat pump is not used.The thermal-electric heat pump 320 Is not required in some applicationsand may be omitted. In some applications, the QCM sensor system 20 mayneed to operate in extreme low temperatures and should, therefore, beassembled accordingly.

The remote user 500 may include, but is not limited to, a computer,computer network, data logger and/or a person. The remote user 500 cansends software commands to the microcontroller 105.

FIG. 2 is a block diagram of an example of a QCM controller 100according to the present invention, shown controlling and monitoring twoQCM sensors 300. The controller 100 includes a microcontroller 105, suchas an AduC812, 8051 (Intel), or any other chip, which can control,either internally or externally, any or all of the following: twodigital-to-analog converters 110, an analog signal multiplexer 125,thermal heat pump circuits 140 and high voltage grids 111. Themicrocontroller 105 may also control QCM power switches 131.

The microcontroller 105 monitors frequency and amplitude of the beatfrequency signal from the QCM sensors 300, two QCM thermal monitoringsignal conditioning circuits from thermal monitors 310, one QCM powersource 158, the microcontroller temperature monitor 150, two thermalmonitoring current sources 144, at least one analog-to-digital converter126 and, if needed, an analog signal multiplexer 125.

The microcontroller also provides a command interface uplink 115 anddata down links 175, 165, or 112, and is responsible for dataacquisition and formatting.

The digital-to-analog converters 110 can support a high voltage gridcircuit 111, which is coupled to the high voltage grid 335 (FIG. 5), orperform analog telemetry 112. The high voltage grid 335 is provided overthe QCM face to getter ionic contamination and can be controlled fromapproximately plus or minus 200 volts.

The command interface uplink 115 supports uplink command, control,calibration and test functions. The beat frequency signal conditioningcircuits 120 include output-limiting amplification circuits withlimiters 121 and zero crossing detectors 122, for amplifying small beatfrequency signals. Amplification is limited to no greater than plus fivevolts (+5 volts) in this example because this is the range of themicrocontroller inputs. The beat frequency signal conditioning circuit120 receives the beat frequency signal from frequency mixing circuit 325(FIG. 1).

The QCM power circuit 130 supplies power to one or more QCM sensors 300.Each QCM power circuit 130 can include QCM power switches 131 forisolating power to one or more of the QCM sensors 300.

The thermal-electric heat pump circuit 140 may be Peltier heat pumps orany type of temperature-regulating device that lowers or raises the QCMtemperature to provide better accreation and that also supportsthermogravimetric analysis (TGA). In this example, each thermal-electricheat pump circuit 140 includes a thermal-electric heat pump controller141 and switch 142, which switches current flow through thethermal-electric heat pump circuit 140 (141, 142). Depending on whichdirection the current flows, the thermal-electric heat pumps 320(FIG. 1) will either heat or cool the QCM quartz crystals 305 and 315.

The QCM thermal monitor sources 145, including thermal monitoringcurrent sources 144, are coupled to QCM thermal monitors 310, which canbe platinum resistive temperature devices (PRTDs), thermocouples, orequivalent devices consistent with the operation of the presentinvention. The QCM thermal monitors 310 are powered by the QCM thermalmonitor sources 145, which include the thermal monitoring currentsources 144.

Still referring to FIG. 2, also shown is a power system 155 forenergizing the QCM sensor system 20, an oscillator 160, digitaltelemetry circuit 165, analog telemetry 112 and digital telemetry clock175.

The power system 155 includes, in this example, a 28-volt source 156,2.5-volt DC-to-DC converter 157, which supplies the thermal-electricheat pump circuit 140, a 5-volt DC-to-DC converter 158, and +5 to −5volt inverter 159. The converter 157 and 158 and inverter 159 may besubstituted, as needed, to accommodate various voltage sources.

In the present example, the oscillator 160 operates at 12 MHz, althoughit could operate at any frequency that is necessary for the parametersof the circuit. The digital and analog data telemetry signals 112, 165,and 175, can be transmitted using, for example, I2C (Phillips), RS-232or equivalent serial communications systems protocols. The telemetrystream may contain Hamming codes, or equivalent, for synchronizing dataframes, and can be transmitted at 2400 baud or higher. Both signalformats include the system's self-monitoring health data of QCM beatfrequency, temperature, voltage amplitude, and duty cycle; current atthe QCM thermal monitor 145 from the thermal monitoring current sources144, the QCM voltage supply 130, and the controller's internaltemperature from the microcontroller temperature monitor 150.

In this example, the microcontroller 105 has a software-defined samplingrate. It is connected to the QCM power circuit 130, QCM thermal monitorsignal conditioning circuits 135, thermal-electric heat pump circuits140, quartz crystal thermal monitor sources 145, and microcontrollertemperature monitor 150. The microcontroller 105 implements programinstructions for converting signals into data records and for addingcodes to the records for data telemetry synchronization purposes. Themicrocontroller 105 further implements instructions for recording datafor subsequent analysis using standard TGA techniques. In accordancewith the disclosed invention, for example, the microcontroller 105instructs the thermal-electric heat pump circuits 140 to heat or coolthe QCM sensor 300 by energizing the thermal-electric heat pumps 320(FIG. 1) while simultaneously measuring the beat frequency signal fromthe beat frequency signal conditioning circuits 120 and the signals fromthe QCM thermal monitor signal conditioning circuit 135. The sublimationand evaporation temperature of a substance can be used to identify themolecular composition of the material based on data recorded in theQCMs. The microcontroller 105 also implements program instructions formeasuring the duty cycle associated with the beat frequency signalconditioning circuit 120. The duty cycle provides additional informationabout the deposition of mass on the QCM sensor 300; it is useful becausein some instances the frequency of the beat frequency may not changewhen liquid is deposited on the first quartz crystal 305. FIG. 3A is athree-dimensional diagram of the physical apparatus of one exampleconfiguration of the QCM sensor system 20 showing the electroniccontroller 100. FIG. 3A shows a modular three-dimensional assemblyhaving controller 100 and associated circuit boards 102 stacked one ontop of the other. The circuit boards 102 can be connected with flexibleconnectors, such as wiring, pin connectors or any other connectors thatare consistent with and support the circuit layout on individual boards.By assembling the circuit boards 102 in this manner, the controller 100may be easily inserted within a housing 400 that provides environmentalcontrol. In addition, this assembly allows easy configuration byreplacing one or more circuit boards 102, depending on the particularfunction of the QCM.

The housing 400 may be fabricated from a metal composite that includes,but is not limited to, aluminum, tungsten, and titanium. It may also befabricated from any other appropriate metal or non-metal composite. Aradiation shielding material is preferred where the sensor system 20 isused in space flight operations.

FIG. 3B is a detailed diagram of the various circuit boards 102 shown inFIG. 3A and an example of their possible connections.

FIG. 4 is a three-dimensional diagram of the QCM controller 100apparatus according to the present invention. FIG. 4 shows thecontroller circuit boards 102 and connectors 103. Assembled as a cube,those circuits requiring a heat sink are located on the outside of theassembly. Further, the circuit boards 102 can be separated by function.This reduces cross talk and better isolates grounds compared to asingle, flat circuit board. The QCM sensor 300 can be connected to thecontroller 100 by at least one cable 340 (FIG. 5). FIG. 5 is a diagramof the QCM sensor system high voltage grid 335 according to the presentinvention. The grid 335 is placed over the face of the QCM sensor 300between the outside environment and the first quartz crystal 305.Between the grid 335 and face of the QCM sensor 300 is an insulator 330.The grid 335 is charged (high voltage, low current) to a potentialeither above or below case ground. When the grid 335 is charged positiverelative to the ground, it attracts negative ions and repels positiveions. When the grid 335 is charged negative to ground, it attractspositive ions and repels negative ions. As the ions are attracted to thegrid 335 they accelerate toward the QCM sensor 300. The interstitialspace within the grid 335 is large enough to allow desired ions to passthrough to the quartz crystal 305. FIG. 6 is a flow chart explaining thesoftware-controlled acquisition and processing of data associated withthe QCM sensor system 20. Step 601 turns on the power to the system.Data acquisition and processing begins with step 602, which initializesthe QCM sensor system 20 default configuration. Initialization mayinclude, but is not limited to, setting the set-point temperature,turning off the power to the high voltage grid 335, setting the samplingtimes, setting temperature ramp speed, reporting any initializationerrors to remote user 500 (FIG. 1), setting the communications protocolfor the microcontroller 105, and setting a reference time for theoscillator (timer) 160, and other initialization routines.

Once the system is initialized, a software subroutine 604 is executed.In the subroutine 604, step 101 starts the subroutine 604. Step 102checks for incoming commands from a remote user 500 (FIG. 1), which isreceived from command interface uplink 115 (FIG. 2). Step 103 detects ifthe command is a new command. If so, step 104 performs the command andthe subroutine starts again. If the command is not a new command, Step103 then proceeds to subroutine 606 wherein, in step 201 the Hammingcode is transmitted. Next, step 202 is executed. This step involvesseparate routines to capture signals associated with the microcontrollertemperature monitor 150 and QCM power circuit 130. In this way, thetemperature of the QCM controller 100 is detected and the voltage supplylevel to the QCM sensors 300 is checked. These signals are thentransmitted to a remote user 500 (FIG. 1).

Steps 203 and 204 are then executed. These steps capture voltage andcurrent signals associated with beat frequency signal conditioningcircuits 120 and quartz crystal thermal monitor sources 145 of therespective QCM's. In this embodiment, the amplitude of the beatfrequency voltage signal is detected, the duty cycle is detected, andthe electrical current delivered to the QCM thermal monitor 310 ischecked. Alternately, the period of the beat frequency signal can bedetected. Further, sampling over a time period equal to several signalperiods allows for an average period to be calculated. These signals arethen transmitted to a remote user 500 (FIG. 1). Another subroutine 608is then run. Step 301 initializes an operational loop. Step 302 thencaptures and transmits the frequency and temperature of one of the QCMsensors. This is done by capturing voltage signals associated withsignal conditioning circuit 120 and QCM thermal monitor signalconditioning circuits 135. These signals are then transmitted to aremote user 500 (FIG. 1).

Subroutine 610 is then run to correct the temperature of the QCM sensor.The set-point temperature is set to the desired QCM sensor 300 operatingtemperature. The measured temperature is then compared in Step 401 tothe set-point temperature. If the measured temperature is higher thanthe set-point temperature, step 402 adjusts the current to thethermal-electric heat pump circuit 140 by way of thermal electric heatpump controller 141 and switch 142, to slowly cool the QCM sensor system300 at a set rate of change in temperature. If the measured temperatureis lower than the set-point temperature, step 403 adjusts the current tothe thermal-electric heat pump circuit 140 by way of the thermalelectric heat pump controller 141 and switch 142, to slowly heat the QCMsensor system 300 at a set rate of change in temperature. If themeasured temperature is equal to the set-point temperature, noadjustment is made. During thermal-gravitational analysis, the set-pointtemperature is set at a maximum value and the current to thethermal-electric heat pump circuit 140 is switched to heat the QCMsensor 300 at a slow rate.

Step 303 is then performed which is the same as step 302 but for thesecond QCM sensor 300. The subroutine 612 is then run. Subroutine 612 isthe same as subroutine 610 except it is performed with respect to thesecond QCM sensor 300. When subroutine 612 is finished the operationloop is ended in step 304. In this example, the subroutine 608 isrepeated 50 times, although this number can be adjusted by the remoteuser 500 in accordance with what is desired from the system. After step304, the system loop is ended and the software-driven data acquisitionand processing subroutines 604 and 606, are repeated starting withchecking for incoming commands from a remote user 500 (FIG. 1).

Thus, the present invention provides a smaller, low power, flexiblecontroller that is also less expensive. The controller of the presentinvention is modifiable by a user so that it can be reconfigurableduring operation.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and applications shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention and theappended claims and their equivalents.

We claim:
 1. An apparatus for controlling a microelectronic sensor andconditioning electric signals having associated therewith electroniccircuits and self-monitoring software, comprising: sensor means, forprecisely detecting temperature and minute changes in mass depositionand outputting a temperature signal associated with a temperature andoutputting a beat frequency signal proportional to said mass deposition;and controller means, operatively connected to said sensor means, formonitoring the health of said sensor means and conditioning said beatfrequency signal, said controller means comprising: a controller thermalmonitor, operatively connected to said controller means, for detecting atemperature of said controller means and outputting a controllertemperature signal; first temperature measuring means, operativelyconnected to said controller thermal monitor, for detecting saidcontroller temperature signal from said controller thermal monitor;second temperature measuring means, operatively connected to said sensormeans, for detecting the temperature signal from said sensor means andoutputting a current; a thermal-electric heat pump circuit, operativelyconnected to said second temperature measuring means, for receiving anelectric current and for raising or lowering the temperature of saidsensor means by switching direction of said electric current to saidthermal-electric heat pump and for turning off said heat pump; signalconditioning means, operatively connected to said sensor means, forreceiving and conditioning said beat frequency signal from said sensormeans; and a microcontroller, operatively connected to said controllerthermal monitor, said first and second temperature measuring means, saidthermal-electric heat pump circuit, and said signal conditioning means,for converting the controller temperature signal, said sensor meanstemperature signal, said second temperature measuring means current,signal, and said beat frequency signal into data records and formanipulating said data records for transmission.
 2. The apparatusaccording to claim 1, wherein said sensor means is a quartz crystalmicrobalance (QCM), comprising: a first quartz crystal, operativelyconnected to said sensor means, for receiving on the surface of saidfirst quartz crystal a contaminant and for outputting a first frequencysignal; a quartz crystal thermal monitor, coupled to said first quartzcrystal, for monitoring and detecting a temperature of said first quartzcrystal; at least one thermal-electric heat pump, mounted in said sensormeans, for raising or lowering the temperature of said sensor means;frequency mixing means, operatively connected to said first quartzcrystal, for mixing said first frequency signal and for outputting abeat frequency signal.
 3. The apparatus according to claim 1, whereinsaid sensor means is a quartz crystal microbalance (QCM), comprising: afirst quartz crystal, operatively connected to said sensor means, forreceiving on the surface of said first quartz crystal a contaminant andfor outputting a first frequency signal; and a quartz crystal thermalmonitor, coupled to said first quartz crystal, for monitoring anddetecting a temperature of said first quartz crystal.
 4. The apparatusaccording to claim 2, wherein said controller means further comprises:remote means, operatively connected to said controller means, forproviding commands remotely; switching means, operatively connected tosaid sensor means, for energizing and de-energizing and switching powerto said sensor means; an uplink circuit, operatively connected to saidmicrocontroller, for receiving commands from said remote means; andtelemetry means, operatively connected to said microcontroller, forcapturing said data records and transmitting said data records to saidremote means.
 5. The apparatus according to claim 2, wherein saidthermal monitor is one of a platinum resistive temperature device,thermocouple, and other thermal monitor device.
 6. The apparatusaccording to claim 2, wherein said sensor means further comprises: ahigh voltage grid, operatively connected to said sensor means, forattracting specific charged particles for mass measurement by switchinga polarity of the high voltage grid to either positive or negative withreference to ground; and an insulator, coupled to said high voltagegrid, for insulating said sensor means from the electric current fromsaid high voltage grid and said sensor means.
 7. The apparatus accordingto claim 4, wherein said controller means further comprises anoscillator, operatively connected to said microcontroller, for providinga timing function for said microcontroller.
 8. The apparatus accordingto claim 3, further comprising a power supply, operatively connected tosaid sensor means, said controller means, and said microcontroller, saidpower supply energizing said first quartz crystal to establish saidfirst frequency signal and wherein said first frequency signal is mixedby said frequency mixing means and captured by said signal conditioningmeans to document frequency shifts to determine mass deposition on saidfirst quartz crystal.
 9. The apparatus according to claim 4, whereinsaid remote means is a computer.
 10. The apparatus according to claim 4,wherein said remote means is a network.
 11. The apparatus according toclaim 4, wherein said remote means is a data collection system.
 12. Theapparatus according to claim 4, wherein said controller means furthercomprises circuit boards, said circuit boards assembled as a cube andmovably connected together by flexible connectors.
 13. The apparatusaccording to claim 4, wherein said controller means is assembled on asingle circuit board.
 14. The apparatus according to claim 4, whereinsaid controller means is assembled on modular circuit boards stacked ontop of one another and movably connected together by flexibleconnectors.
 15. The apparatus according to claim 12, wherein saidcircuit boards have mounted thereon said controller thermal monitoringmeans, said temperature measuring means, said thermal-electric heat pumpcircuit, said signal conditioning means, said microcontroller, saidoscillator, uplink circuit, and said telemetry means.
 16. The apparatusaccording to claim 12, wherein said circuit boards are mounted inside aprotective housing unit constructed of one of a metal alloy andcomposite.
 17. The apparatus according to claim 13, wherein said circuitboard is mounted inside a protective housing unit constructed of one ofa metal alloy and composite.
 18. The apparatus according to claim 14,wherein said modular circuit boards have mounted thereon said controllerthermal monitor, said first temperature measuring means, saidthermal-electric heat pump circuit, said signal conditioning means, saidmicrocontroller, said oscillator, uplink circuit, and said telemetrymeans.
 19. The apparatus according to claim 14, wherein said modularcircuit boards are mounted inside a protective housing unit constructedof one of a metal alloy and composite.
 20. A self-monitoring apparatushaving electronic circuits, sensors and software for monitoring andcontrolling a quartz crystal microbalance (QCM), comprising: sensormeans, for precisely detecting minute changes in mass depositionthereon, said sensor means comprising: a first quartz crystal,operatively connected to said sensor means, for receiving a contaminanton the surface of said first quartz crystal and for outputting a firstfrequency signal for determining a mass of said contaminant; a secondquartz crystal, operatively connected to said sensor means, foroutputting a second frequency signal; frequency mixing means,operatively connected to said first and second quartz crystals, forreceiving and mixing said first and second frequency signals andoutputting a beat frequency signal; a quartz crystal thermal monitor,mounted in said sensor means, for detecting the temperature of saidfirst and second quartz crystals and outputting a thermal monitortemperature signal; at least one thermal-electric heat pump, mounted insaid sensor means, for raising or lowering the temperature of saidsensor means; and a high voltage grid, operatively connected to saidsensor means, for attracting specific charged particles for massmeasurement by switching a polarity of said high voltage grid to eitherpositive or negative with reference to ground; an insulator, coupled tosaid high voltage grid, for insulating said sensor means from anelectrical current from said high voltage grid and said sensor means;controller means, operatively connected to said sensor means, formonitoring the health of said sensor means and conditioning said beatfrequency signal, said controller means comprising: a quartz crystalenergizing circuit, operatively connected to said controller means,comprising: a quartz crystal voltage-regulating circuit, operativelycoupled to said first and second quartz crystals, for regulating thevoltage across said first and second quartz crystals; a signalconditioning circuit, operatively connected to said quartz crystalvoltage-regulating circuit, for receiving said beat frequency signal;and an amplification circuit, operatively connected to said signalconditioning circuit, for receiving and amplifying said beat frequencysignal; a quartz crystal thermal monitor circuit, operatively coupled tosaid controller means, comprising: a quartz crystal thermal monitorvoltage-regulating circuit, operatively connected to said quartz crystalthermal monitor circuit, for regulating the voltage across said quartzcrystal thermal monitor; a quartz crystal thermal monitor temperaturedetecting circuit, operatively connected to said quartz crystal thermalmonitor voltage-regulating circuit, for receiving temperature signalsfrom said quartz crystal thermal monitor and outputting a voltagesignal; and a thermal-electric heat pump circuit, operatively connectedto said quartz crystal thermal monitor circuit and said sensor means,for switching a current to said thermal-electric heat pump to heat orcool said first and second quartz crystals; a controller thermalmonitoring circuit, operatively connected to said controller means,comprising: a controller thermal monitor, operatively connected to saidcontroller means, for detecting the temperature of said controller meansand outputting a controller temperature signal; a controller thermalmonitor voltage-regulating circuit, operatively connected to saidcontroller thermal monitor, for regulating voltage across saidcontroller thermal monitor; and a controller thermal monitor circuit,operatively connected to said controller thermal monitorvoltage-regulating circuit, for receiving said controller temperaturesignal and outputting a voltage signal; an analog to digital converter,operatively connected to said controller means, for converting said beatfrequency amplitude, said QCM voltage signal, said QCM thermal monitorvoltage signal, said thermal monitor current and said controllertemperature signal from analog to digital; a digital to analogconverter, operatively connected to said controller means, forcontrolling said high voltage grid circuit; a power switch, operativelyconnected to said controller means, for energizing or de-energizing saidsensor means; a microcontroller, operatively connected to said sensormeans and said controller means, for converting said beat frequencysignal, said QCM thermal monitor voltage signal, and said controllertemperature signal into data records and manipulating said data recordsfor subsequent data telemetry; an oscillator, operatively connected tosaid controller means, for providing a timing function for saidmicrocontroller; remote means, operatively connected to said controllermeans, for providing commands remotely; a telemetry means, operativelyconnected to said controller means, for capturing said data records andtransmitting said data records to said remote means; and an uplinkcircuit, operatively connected to said controller means, for receivingcommands from said remote means; and a power supply, operativelyconnected to said sensor means and said controller means, for energizingsaid apparatus.
 21. The apparatus according to claim 20, wherein saidmicrocontroller calculates a duty cycle and waveform associated withsaid beat frequency signal and converts said signal into one or moredata records.
 22. The apparatus according to claim 20, wherein saidremote means is a computer.
 23. The apparatus according to claim 20,wherein said remote means is a network.
 24. The apparatus according toclaim 20, wherein said remote means is a data collection system.
 25. Theapparatus according to claim 20, wherein said controller means comprisescircuit boards, said circuit boards assembled as a cube and movablyconnected together by flexible connectors.
 26. The apparatus accordingto claim 20, wherein said controller means is assembled on a singlecircuit board.
 27. The apparatus according to claim 20, wherein saidcontroller means is assembled on modular circuit boards stacked on topof one another and movably connected together by flexible connectors.28. The apparatus according to claim 25, wherein said circuit boardshave mounted thereon said quartz crystal energizing circuit, said quartzcrystal thermal monitor circuit, said controller thermal monitorcircuit, said digital to analog converter, said analog to digitalconverter, said microcontroller, said oscillator, said remote means,said telemetry means, and said uplink circuit.
 29. The apparatusaccording to claim 25, wherein said circuit boards are mounted inside aprotective housing unit constructed of one of a metal alloy orcomposite.
 30. The apparatus according to claim 26, wherein said circuitboard is mounted inside a protective housing unit constructed of one ofa metal alloy and composite.
 31. The apparatus according to claim 27,wherein said modular circuit boards have mounted thereon said quartzcrystal energizing circuit, said quartz crystal thermal monitor circuit,said controller thermal monitor circuit, said digital to analogconverter, said analog to digital converter, said microcontroller, saidoscillator, said remote means, said telemetry means, and said uplinkcircuit.
 32. The apparatus according to claim 27, wherein said modularcircuit boards are mounted inside a protective housing unit constructedof one of a metal alloy and composite.
 33. A system for sensing andmeasuring the mass of solid or liquid matter, mass of charged particles,and molecular composition of solid or liquid matter, and for monitoringand controlling electric signals, said system comprising: a quartzcrystal microbalance (QCM) sensor comprising: at least one quartzcrystal, operatively connected to said QCM sensor, the surface of saidat least one quartz crystal receiving contaminants and outputtingfrequency signals; a frequency mixing circuit, operatively connected tosaid at least one quartz crystal, for receiving said frequency signalsand for outputting a beat frequency signal; at least one least onequartz crystal thermal monitor, operatively connected to said at leastone quartz crystal, for detecting a temperature of said at least onequartz crystal and for outputting a quartz crystal temperature signal;at least one thermoelectric heat pump, operatively connected to said atleast one quartz crystal thermal monitor, for adjusting the temperatureof said at least one quartz crystal; and a high voltage grid,operatively connected to said QCM sensor, for attracting specificcharged particles for mass measurement and receiving a voltage signal; acontroller, operatively coupled to said QCM sensor, said controllercomprising: signal conditioning means, operatively connected to saidcontroller, for conditioning the beat frequency signal from saidfrequency mixing circuit; quartz crystal thermal monitor measuringcircuit means, operatively connected to said controller, for measuringthe temperature signal from said at least one quartz crystal thermalmonitors; thermal-electric heat pump circuit means, operativelyconnected to said controller, for increasing or decreasing the currentdelivered to said at least on thermal-electric heat pump; a controllerthermal monitor, operatively connected to said controller, for detectinga temperature of said controller and outputting a controller temperaturesignal; high voltage grid circuit means, operatively connected to saidcontroller, for outputting a voltage signal to said high voltage grid;and a microcontroller, operatively connected to said controller, forcommunicating between said controller and a remote user; remote means,operatively connected to said controller, for providing commandsremotely; and program means, associated with said microcontroller, saidprogram means containing one or more instructions for controllingvoltage to said high voltage grid circuit, for controlling current tosaid at least one thermal-electric heat pump, and for capturingelectronic signals from said signal conditioning means, said quartzcrystal thermal monitor measuring circuit means, and for converting saidsignals into data records, and for receiving commands from said remoteuser.
 34. The system according to claim 33, wherein said system is usedin a chemical deposition process.
 35. The system according to claim 33,wherein said system is used in a space flight operation.
 36. The systemaccording to claim 33, wherein said system is used to monitor forchemical contamination in an enclosed or ambient air environment. 37.The system according to claim 33, wherein said system is used to forbiological detection.
 38. A computerized method for controlling a quartzcrystal microbalance (QCM) sensor, said method comprising the steps of:(a) initializing system variables and establishing default and set-pointvalues; (b) energizing a potential across QCM sensor system terminals,thereby energizing QCM sensor quartz crystals, a thermal-electric heatpump, and a high voltage grid contained within the QCM sensor; (c)detecting the voltage signal amplitude and voltage signal frequency ofthe QCM sensor system quartz crystals, the voltage amplitude of the QCMsensor system thermal monitor, and the current of the controller thermalmonitor and QCM sensor power supply, and producing individual signalsrepresentative thereof; (d) amplifying the quartz crystal voltageamplitude signal and calculating the duty cycle and waveform thereof;(e) supplying the signals detected in said step (c) and the calculatedduty cycle and waveform calculated in step (d) to a microcontroller forconversion into data records; (f) comparing the data records to thedefault or set-point values; (g) adding synchronization codes to thedata records; (h) transmitting the data records through a wired orwireless communications system to a remote computer or computer network;(i) checking and receiving incoming commands from the remote computer orcomputer network; and (j) adjusting the voltage supply to thethermal-electric heat pump as a result of the incoming commands or thedeviation from the default or set-point values.
 39. The method accordingto claim 38, wherein said method further comprises the steps of: (k)slowly heating the QCM sensor quartz crystals and detecting the voltagesignal amplitude and voltage signal frequency of vibration of the QCMsensor system quartz crystals over time; (l) calculating a sublimationand evaporation temperature corresponding to the material deposited onthe QCM quartz crystals; and (m) supplying the voltage signal amplitudeand voltage signal frequency associated with the QCM sensor systemquartz crystals and the sublimation and evaporation temperaturecorresponding to the material deposited to the microcontroller forconversion into data records.
 40. The apparatus according to claim 1,said controller further comprising a power switch, operatively connectedto said controller means, for energizing and de-energizing and switchingpower to said sensor means, and wherein said microcontroller furtherconverts a voltage signal from said power switch into data records. 41.The apparatus according to claim 1, wherein said sensor means is aquartz crystal microbalance (QCM), comprising: a first quartz crystal,operatively connected to said sensor means, for receiving on the surfaceof said first quartz crystal a contaminant and for outputting a firstfrequency signal; a second quartz crystal, operatively connected to saidsensor means, for outputting a second frequency signal; a quartz crystalthermal monitor, coupled to said first and second quartz crystals, formonitoring and detecting a temperature of said first and second quartzcrystals; at least one thermal-electric heat pump, mounted in saidsensor means, for raising or lowering the temperature of said sensormeans; and frequency mixing means, operatively connected to said firstquartz crystal, for mining said first and second frequency signals andfor outputting a beat frequency signal.
 42. The apparatus according toclaim 12, wherein said circuit boards have said power switch mountedthereon.
 43. The apparatus according to claim 15, wherein said circuitboards have said power switch mounted thereon.
 44. The apparatusaccording to claim 18, wherein said circuit boards have said powerswitch mounted thereon.
 45. The apparatus according to claim 28, whereinsaid circuit boards have said power switch mounted thereon.
 46. Theapparatus according to claim 31, wherein said circuit boards have saidpower switch mounted thereon.
 47. The controller according to claim 1,wherein said thermal-electric heat pump circuit is operatively connectedto said microelectronic sensor.
 48. The apparatus according to claim 3,further comprising: a second quartz crystal, operatively connected tosaid sensor means, for outputting a second frequency signal as areference for said first quartz crystal.
 49. The apparatus according toclaim 4, wherein said controller means is a flat board assembly.